EPIC!! Jeep Blown Head Gasket but Normal Compression Returns For Experiments + Blue Devil Fix

The jeep is back for me to do some experimentation on it to find out why the compression is normal despite it having a confirmed blown head gasket, and also we look at high and low tech methods on how we can diagnose this issue if it happens. Plus bonus- we try to fix it with Blue Devil Liquid Gasket Repair.
This Video is Part 3 of a 3-Part series.
Part 1 is the original diagnosis of Vehicle when it first came in: • Did Liars and Thieves ...
Part 2 is a discussion and Q+A on this unusual issue: as others have seen this before too. • When Compression Tests...

[@michael.sierra]

Bars HG-1 worked for me both in a Ram 4.7 that lost all its coolant due to a leaky heater core and subsequently overheated and then in my a 97 Suburban 5.7 that got coolant into one cylinder because I was sloppy when doing some other work and I cranked it over and blew the head gasket. Both of them were running rough and billowing white. Each one got a single treatment of Bars HG-1 and after that, no coolant loss, ran smoothly, no white smoke, and passed CA smog tests. Total success! Both of those vehicles were sold to people I know (I did disclose the HG-1) and both ran and drove fine until they ended up junked for other reasons.

[@lance1097]

About 15 years ago a shop owner asked me what I would've been if I wasn't a mechanic, and I said a scientist. Maybe that's why I like your channel. 😃

[@SchrodingersBox]

I once said the opposite hahahah! Seriously, I did!

[@scientist100]

@@SchrodingersBox sometimes I wish I was a design engineer. I love making stuff and troubleshooting.

[@rightconditions2010]

​@Schrodingers Box, what do you enjoy the most, Matt? I wish you were a full-time mechanic. You 've been a blessing for learning.

[@SchrodingersBox]

So actually I do have plans of transitioning to making KZbin videos full time within the next few years. I believe I can pull that off as a way to retire early. We’ll see!

[@scientist100]

@@SchrodingersBox good call. You've built a big crowd. Maybe bring more of that oscilloscope theory and invent ways to diagnose better.

[@brucet.6967]

I seldom respond to any KZbin videos, but I’ve got to say, this 3 video series are some of the absolute best I’ve ever seen. Phenomenally good and thorough job!

[@SchrodingersBox]

what a compliment!! thank you!!

[@cindergutierrez5658]

@@SchrodingersBox I'll be in Colorado soon I would love to volunteer/spend time with you, can we make that happen I've been seeing your videos since I started fixing cars(when i sucked).

[@SchrodingersBox]

Let me know when you are here!

[@chucksneed6440]

Got a little project farm esque with the bluedevil testing at the end. I was surprised to see it helped as much as it did. I agree with the notion that this is in fact one of your best video series to date. I enjoyed it all and learned something new. You're very good at teaching and demonstrating concepts I'd typically find troublesome understanding.

[@FreeKanal]

What a great way to check for combustion chamber compromise(CCC?), this Combustion Chamber Compromise Check(CCCC?) is the another best thing i learned from You ! Thanks Matt ! Amazing episode !

[@DuaneDonaldson]

In the first video, I was expecting you to purchase this loss, but I am happy to see it come back. I don't do single oil changes on jobs like this, I will price in 2 minimum and 4 with very bad contamination jobs also using transmission fluid as the cleaner on the first 3 changes. DO NOT use an injector as a sync, you mentioned not knowing the firing order, its more of a pain in the ass to figure out when an injector actually fires unlike diesel or GDI that fire near TDC, different cars fire injectors at different times, unless you keep records don't do it. As I mentioned in video 1, there is a delay in the pressure but it's fairly quick after #7, in this case. The vacuum gauge test did not tell us anything that we didn't already know, there is a compromise somewhere, you should have then used the gauge and pulled the #7 spark plug based on the P0307. I am thinking of no more pulse and the problem identified in the case of a single-cylinder compromise. I did watch all of your videos, sorry I don't remember how all you ID a blown head gasket in an older video but what you have just shown is a quick increase of pressure in the cooling system before the coolant has time to heat up and create pressure, Known compromise this way also but where, vacuum gauge and remove the suspected spark plug. This seems like the best DIY procedure, thanks for the great video. 2 videos before this and nobody offered you to download the Microsoft cylinder pressure overlays software for free? There is a learning curve, don't forget about valve overlap around 180* and valve timing is not exactly at TDC & BDC. kzbin.info/www/bejne/j3eZZGCwjMaXq8U

[@scientist100]

I always swore by the scope because of Bernie from ATS. Although I always loved using some sort of diagnostic tool, the scope was a game changer when I found out about it.

[@SchrodingersBox]

I use the scope almost every diagnostic now!!

[@franciscoxaviergonzalezrom4648]

Bro you are a scientist! Average auto technician does not get those kind a conclusions, even engineers don´t relate theorical knowledge with practical experience..... Thank you! English is not my mother tongue but I get you!

[@SchrodingersBox]

Wow, thanks, and I am glad you get it!! incidentally if you didn’t know, I am actually a scientist. it’s what I do for a living. cars is just my hobby.

[@franciscoxaviergonzalezrom4648]

@@SchrodingersBox I didn't know! If this is your hooby I imagine how good your work as a scientist it is! Good job bro! I'd like to join to you paid channel.... Thank you!

[@calholli]

Ivan at "Pine Hollow Auto Diagnostics" has a couple of transducer kits that he sells for under $200 if I remember correctly. One is like a 600 psi max and the other is for more precise measurements at lower pressures, like under 100 psi I believe. (both for use with the pico scope).

[@InsideOfMyOwnMind]

i was going to recommend his kit but I knew you would so I sat back and let it happen.🤣

[@sheerwillsurvival2064]

I looked for it on his Amazon store but couldn’t find any 🤷‍♂️

[@calholli]

@@sheerwillsurvival2064 Yeah idk. He was selling them before last Christmas. lol.. It's been awhile.

[@sheerwillsurvival2064]

@@calholli darn I wanted one

[@Mr2004MCSS]

Ivan sells his transducer kits for $450 and they are on his website.

[@christopherbriden8403]

Crazy video. This is the kind of stuff nobody else is putting up. Nice work. Enjoyed every minute of the diagnostic on this car.

[@SchrodingersBox]

Really like the “no one else is putting this up”- that is exactly what I strive for, so thank you for recognizing that!

[@christopherbriden8403]

The bore scope that looks backwards at the leak almost caused me to stand up and clap! Very nice tool….

[@SchrodingersBox]

Hahaha isn’t it awesome!!!! I do have another borescope that doesn’t have that feature and it’s now useless lol.

[@bradbeck2601]

My mothers car had what I believed to be a bad head gasket. The vehicle would overheat in just a minute or two of idling and a chemical block test showed an absurd amount of combustion gases bubbling through my tester. On a small budget and time restraint I replaced the head gaskets for her that night but it didn't help at all. Either a crack in the head or cylinder wall I believe. As a last ditch effort to get her car back to her cheaply and quickly I used BlueDevil. It's been running for almost 3 years now with no issues at all. Well, except I did end up flushing the heater core a year later. I actually mixed the Blue devil completely into all of the coolant outside of the vehicle then added it to the vehicle (because the car would only idle for a minute and because I didn't think I would get good flow from how the coolant bottle was set up). After a minute or so the car was overheating so I shut it down, completely discouraged. When I started the vehicle back up, no overheat condition and it hasn't overheated ever since. I've done a chemical block test a couple times since and have no combustion gases in the cooling system now. I would normally never recommend the stuff, BUT, If you're in a pinch, BlueDevil really does work even on major breeches of the coolant / combustion barrier.

[@palharley]

Glad to see that never say never doesn't prevent you from experimenting with snake oil fixes. I'm sure that this product won't fix an enormous problem. Please keep us informed, great series.

[@crasher88]

great video series. Another technique for using the pressure transducer on the radiator fill hole. Once one gets to the point where you were with the transducer connected to the radiator and can see the pressure rising during cranking you can one by one remove the spark plugs from each cylinder until the pressure increase stops. When it stops rising during cranking you have found the problematic cylinder(s).

[@SchrodingersBox]

Great idea! It’s a bit problematic for engines with a bank under the intake- it can take hours to access the cylinders on some cars. I need to think of a low tech way to do the cylinder identification without removing plugs.

[@helgikristjansson4702]

Great series of videos. Thanks again Matt for taking the time and effort to educate us. One of a kind series of videos.

[@SchrodingersBox]

Thanks my friend. Yes this series was a really important one as I have struggled with this phenomenon for years now. Its great to finally put it to bed and know I can address if this issue ever happens again!

[@billyr9840]

Wow, you hit it out of the ball park with this Matt ! Awesome vid !

[@SchrodingersBox]

thanks Billy! It is one of my favorites for sure. Always learning something new.

[@frugalprepper]

Toyota Prius blows head gaskets. I have used Bars Leak Head Seal Blown Head Gasket Repair on several of them in the last few years. They are all still driving around fine. Sounds like they are good to sell it now!

[@rwrobs777]

Hi Matt !!…C5 Diag here…THANKS for the shout out and I’m VERY happy to have sent along my old Picoscope to you and I just hope that your subscribers who are Techs in either an Independent shop or a Dealership see what a VALUABLE piece of diagnostic equipment a scope is and after watching you use it have decided to make the leap and start using one themselves…would love to hear from them if they have started using one because of you. I would advise you suspend the WPS with a bungee cord where vibrations from the car won’t affect it…keep up the great work !!…BTW the max input voltage on your 4225 is 200 volts I believe and you can also pick up a 10 or 20X attenuator if need be.

[@SchrodingersBox]

Thanks Rob. I have a 20X attenuator actually- I just knew from previous work on this car off camera that the voltage was within range so that was just for show hahaha. I would never put the pico at risk -- well, again. Remember when I almost zapped it on the very first video I did with it trying to chase a misfire and it happened to be a worn spark wire sitting just inches from the scope hahaha!!!!

[@RoRo-kc8zv]

I’ve learned so much from super smart Matt then I have at mechanic school 👏

[@SchrodingersBox]

Awwwww thanks!!!!

[@donkaiser6704]

A rigorous treatment of as subject that's important, even to us DIY'ers. Thanks much!

[@TheBry_Guy]

Very good vid. I spend hours a week watching car repair vids and now and again you watch a vid that just makes things CLICK. The concept morphs in your mind from a partially remembered string of words to a clear graphic with arrows and labels. Thank you.

[@SchrodingersBox]

Really appreciate the comment thank you!!

[@advancedleveldiagnostics]

Great video, I appreciate all the work you put in to prove the point! I would recommend you get a pulse sensor they are relatively inexpensive, (Jarhead Diagnostics makes one for $90) and they are really sensitive to changes in pressure so instead of seeing steps in pressure you'll see a spike on number 7.

[@SchrodingersBox]

Good to know!! Thanks!!

[@DanielSan-ch7dr]

​@SchrodingersBox I use sealtite in Australia it's basically the same thing but it looks like liquid copper and it's gotta be used with pure water and idled until the bubbles stopped and then let cool down and repeat for a few cycles. Mine had 3 leaking cylinders so severe that I hydrocked the engine during the pressure test at 20psi engine off had to remove all plugs and pressure tester to clear water and when I tried to restart with tester cap still on it shot out 2ft like a water pistol. Even for me to fix at cost was nearly 1k with my own labour and maybe 2 days works or 13 dollars and a few hours while I cut and polished the car. Mazda has a clear header tank so I could physically see the large bubbles returning to the tank and they gradually got smaller and smaller until after maybe 2hrs they completely stopped and my header tank smells like petrol now. It fixed it perfectly and another car 2 leaking cylinders with the choice of 400 repair or 1800 they took the chance and 6months later hasn't leaked a drop. Only works when water into combustion not water into oil as the glass sets upon meeting the combustion gases temperature. Also on your cam video the cylinder top was completely steam cleaned of all carbon indicating its burning coolant in there and I bet if you checked a good cylinder you'd find carbon on the tops.

[@labodiesel7443]

AT 50:15 IN THE VIDEO, THE REASON WHY THE COMPRESSION DO NOT GO IN THE GASKET LEAK IS CAUSE BY THE LEAKAGE BY THE RINGS IN THE OIL

[@Muelli1000000]

Great Video! I also had good experience with bars head gasket sealer. It held for about 2000mls before I had to use it again. But on my car I had much bigger compression losses in multiple cylinders.

[@edwardturello2782]

This is probably the best instructional video I have ever seen. The effort and analisys you put into these videos clearly shows the passion and the scientific approach that you were trained on. Thanks so much for showing the methods used for this type of problem, including the Blue Devil fix, which I never even heard of before

[@SchrodingersBox]

Thanks my friend. Thanks for all your years of watching too!!

[@Christdeliverme]

Lol, i loved how excited you got in this video. Great job with explanations and thoroughness.

[@travissheehan6082]

Great video. I’ve always wanted to see an actual valid test of one of those sealer snake oil fix it in a cans. Can’t wait for the follow up.

[@Parknest]

Matt, this appears to be the perfect application for the liquid head gasket repair. There was clearly coolant getting into a cylinder from the white smoke. The fact that there was no loss of compression should indicate the severety (or lack) of the leak. Leaks of such a small size cause the usual tests to be misleading. Hopefully, the liquid gasket repair will at least buy the owner some time.

[@michaelgrubbs1618]

Yes Matt. Right off the Hop. It's probably cuz things are going up and down fast enough. The little bit of heat generated. And it's a small compromise. In the respect of compression. But under extreme heat has enough to make this engine fail. And overheat. As always nice job

[@SchrodingersBox]

Yep- we will confirm your suspicions!

[@pauldavies4955]

Great video. I absolutely love how took the time to show and prove scientifically what the problem was.

[@SchrodingersBox]

Yes I want to leave no possibility of overlooking anything. We know 100% that the tests work, we know 100% why, and we know 100% how.

[@calholli]

The "NEW" nomenclature that you are looking for is "ingress". There is ingress of coolant into the cylinder. The ingress could be through a crack, head gasket, stuck valve, blowby, etc. or all the above-- who knows. The point is that there is a break in the seal somewhere. Ingress is the word you're looking for, rather than saying "blown head gasket"; since the exact cause is yet to be determined definitively.

[@jum5238]

He covered that in (I think) video 2.

[@cwstout1]

I love your videos, the way you explain things keeps me mesmerized, something about your speaking voice. Anyway being a molecular biologist that I assume studies cell structure and stuff, that perhaps the molicules in BlueDevil has some kind of structure. Sometimes I feel like I am surrounded by molecules. I can't wait to see the follow up on this vehicle. Now I have to look for that video of Scotty Kilmer blowing cigar smoke into a hose. Have a great day my friend.

[@harleyMnP45]

What do you think about using a Redline smoke machine? It measures leaks in thousands of an inch. I think the cylinder leakdown gauges have some compensation for leaks past the rings so not so accurate. 2 cylinders could be tested for comparison and even add some oil to the cylinder to fill the ring gap. Just brainstorming, thanks! Awesome video and I love the scientific method. Also, I have used blue devil on a couple occasions. Where shortly after starting the engine the exhaust gas comes blowing out the radiator. It'll turn the blue litmus fluid green or yellow every time. Rarely have I seen exhaust gas coming out from the radiator immediately after starting. Once the engine starts to warm up it seems the gap will open wider and reveal the issue. Remove t-stat, drain coolant, flush system with good degreaser flush, flush with clean water, add blue devil, follow directions exactly and then drain out, new thermostat and refill with coolant. Two that I know of have been going for years and never blew out again. For the record, I did not use the pour and go kind.

[@SchrodingersBox]

I have a redline smoke machine but honestly I don’t really find I need the leak measurement very often. Maybe once a year. I use my autoline pro 99% of the time.

[@mph5896]

I bought a new casserole dish today, pretty excited about that.

[@SchrodingersBox]

HAHAHAHAHAHAHA well enjoy the casserole while watching the movie!

[@chrisi1909]

This is a top Part 3 ! I as well would have said that this snake oil will not change anything - was very intresseting to see any difference. Time will tell.

[@SchrodingersBox]

Yes I was just shocked. Kind of mad actually hahahaha

[@Darkshadow10157]

Thanks for the excellent video series. I really appreciate the scientific approach you take with testing. There aren't many channels that go beyond finding what works and actually get to why it works. That's so critical to understanding systems and really scratches that mental itch for me. Thank you so much! Glad you tried the blue devil too. I'm sure those people are very happy. I owned a similar vehicle with combustion gasses getting into the cooling system after an overheat. I didn't do a compression or leak down test (of course), but I did do a chemical block test. It failed before using a similar product called K-seal, and passed afterwards. That car kept going without issue for another 2 years before finally rusting out and going to the crusher. I'd never consider such a thing to be a permanent fix, but it can certainly buy you some time to make a better purchase decision when replacing the vehicle.

[@mechanicmatt871]

I really enjoyed this video, this is exactly why I watch your channel. Thanks for taking the time to show that my last suggestion of removing the cap still doesn't help. Strange that battery voltage relative compression showed a change although the amp clamp RC didn't. Very educational, thanks Matt

[@SchrodingersBox]

Thanks Matt. The Voltage and amp clamp showed the same exact thing. Neither was able to detect a compression loss. You may be confusing it with the radiator neck tranducer test which did catch the cooling system pressure increase?

[@mechanicmatt871]

Yes I made mistake there. The whole three part series has been a huge eye opener for me. Thanks for everything you do. Really appreciate it. The transducer on the rad with a sync was great. I have never bothered looking any further, if the RC test looked good. Now I know I'll have to rule out a head gasket fault as well. Thanks for sharing your knowledge, you are making lots of us better mechanics.

[@SchrodingersBox]

Absolutely. I will admit that even 5 years ago I would have said this car needs an intake manifold because that’s exactly what I did the first time I ever saw this issue on a Toyota but I discovered the intake manifold was a dry (no coolant passages) design. And even then I refused to believe the compression test lied. But the leakdown proved it and ever since then it made me pay attention. On this latest car I decided I really need to study this problem because it isn’t all that rare.

[@tomctutor]

I had misfires and water overheat issues on my Lexus Is220 (diesel). I used SteelSeal after doing a positive chemical test. The sealant worked and that was fine for about 12 months. I had to then change my water Pump but the overheating due to cylinder leak never reappeared. This substance changes into flexible glassy like substance on heating, looks a bit like epoxy when it hardens and is quite strong. It will only harden on high temperature typical of a firing cylinder but remains liquid circulating with the radiator, i.e. only hardens in the gasket or block crack. 😏

[@davyarthurs]

Look forward to the follow up in part 4, as like you I’m very sceptical of these ‘magical’ head gasket fixes. Hopefully this ‘fix’ will buy the owner some time, but my money is on it isn’t going to last forever. Great video series!

[@SchrodingersBox]

I will absolutely follow up!!!

[@jum5238]

@@SchrodingersBox Since you tried a "sizzle test" with that stuff, and it hardened, I imagine it would similarly harden in the presence of a hot flame from a firing cylinder. The question is how durable that hardened substance is.

[@iceyu2235]

I've always wondered in what situation that stuff would actually be helpful lol. Now I know! Thanks Matt!

[@johnjonz2472]

The odds of a video like this, right after the 2 previous videos . Awesome! Well...for us.

[@SchrodingersBox]

It’s only because they brought the same car back. I knew it could be years and years before I had another chance so I contacted customer and asked them if they could bring the car back so I can do another video, I would do a free blue devil treatment in return. They agreed so we got the second chance with this car.

[@johnjonz2472]

@@SchrodingersBox oh I see. Awesome, nonetheless!

[@rgmeyers66]

Best ever, sincere thanks for gallant efforts and covering all possibilities.

[@SchrodingersBox]

I always try!! Thanks for appreciating it. Most people wouldn’t understand how necessary it is.

[@christopherneale13]

Never seen the sizzle test awesome is that, great video really eye opening

[@SchrodingersBox]

Thank you! Yes the original sizzle test is outlined in my video "12 way to test for a blown head gasket". It was taught to me by a guy at the junk yard.

[@rosewd2]

im surprised the blue devil really worked that well. it will be interesting to see what happens after a week of driving the car around.

[@SchrodingersBox]

Totally!! I will follow up on it for sure!

[@stuzman52]

Just a few comments Matt. On your WPS500 pressure transducer, there are three ranges. Range 1 = -15 to 500psi, range 2 = -15 to 50psi and range 3 = -5 to 5psi. Seeing that the pressure was small on the vacuum/pressure gauge, range 3 would be a good choice. And with this range set in the software, you would get a quantitative value for pressure. Always a good idea to use an attenuator on the scope especially when looking at primary ignition voltage. I have seen 350VDC on some of Ford's coils. And when you put the rulers to measure 720° of a firing event as you mentioned there would be 90° between each cylinder's firing event. You can set the rulers to partition it for whatever the number of cylinders are. For example with the eight cylinder engine you have, set the 'Rotation Partition' number to eight. The rulers will be divided into eight partitions with 90° between each ruler. And if a six cylinder, the number would be six which divides the rulers every 120° and a four cylinder would be 4 which divides the rulers every 180°. Have a great evening Matt!

[@SchrodingersBox]

Thanks as always Terry!!!!! Great advice and yes I did figure out the WPS and the Pico calculation during the hour I was waiting.

[@brownwrench]

MY 4.7 also had gasket issues that did not vapor even. My guess it was #3 because it threw a misfire code 303 on 2 and only 2 occasions. Did the Blue Devil and no more issues. The misfire code has not reappeared again either.

[@brownwrench]

Wow! Love the articulating scope tip.

[@InsideOfMyOwnMind]

That was cool but If my doctor ever took out one of those and demoed it like Matt did I would run!

[@SchrodingersBox]

HAHAHAHA I was thinking the same thing!!!!!

[@brownwrench]

@@InsideOfMyOwnMind 😆

[@mlstrawxj]

I made a transducer just for checking radiator pulses using a piezo guitar pickup and some PVC pipe. I connect it to the radiator using my radiator pressure tester hose to the filler neck.

[@SchrodingersBox]

Yea I have heard others doing same and I also considered as much myself however I decided to get the official transducer because I am working on other peoples’ cars so I want to make sure I have the most reliability and accuracy.

[@jum5238]

@@SchrodingersBox Look, if it's the PVC plastic hanging out of the radiator that you're worried about looking too ghetto for you, Krylon sells a shiny black paint that....

[@Gelis8]

This was an interesting video. I have a similar fault on my boat engine VolvoPenta V6 (GM as a basis). Combustion gases in the fresh water cooling. Very little, barely detectable with blue indicator fluid. Engine runs hot but not boiling 96-98°C. Comp. test OK, Leak-down OK, Pressure test of cooling system OK, maintains the same pressure over 4 hours. Sent for Blue Devil from the USA (not available for purchase in Sweden). Have had the cylinder heads removed and leveled them. Look for cracks with penetrating paint, both in the heads, blocks and cylinders. Everything looks ok but the error persists, so I'm clearly missing something. So let's see if Blue Devil makes any changes.

[@Gelis8]

Looks like BlueDevil is working, temperature is at a steady 84°C. No exhaust gases in the fresh water cooling. The indicator fluid is still blue after half an hour of testing. Only driven with moderate load yet, but will test full load. So far promising results

[@charlesgould8436]

In early 80s not even 10yo, from a charity at Christmas, I got some kind of circuit maker toy:) it looked like a connect 4 game:) I never fully understood what i was doing, just followed directions. There was Noone anywhere I knew of that could even begin to explain

[@SteveLowe65]

Great video, loved all the different methods and scientific discussion.

[@JustAnother_Irishman]

Sir, you are a genius. Thank you for sharing.

[@lance1097]

You can get a radiator pressure tester kit for less than $200 that comes with most radiator caps that have a nipple on the top for hooking a hose up to.

[@calholli]

That rubber cone is all you need for 95% of vehicles. Sometimes you may have to plug the little overflow tube.

[@jum5238]

@@calholli Where do you find that rubber cone?

[@reneneron2971]

Glad to see the pressure test on the radiator system worked. As for the additive, not a good solution. Something I suspect someone to use to “fix” the issue and then sell the problem to someone else. Analogous to using fix a flat to repair a leaking tire. That goop is now throughout the cooling system, not just at the leak. How do you get it back out? It will also plug passages thoroughly the cooling system.

[@carnivorebear6582]

In my experience if you do a good job bleeding cooling systems after adding leak sealant and replacement coolant then it doesn't tend to cause problems and can be a quick, cheap and effective temporary fix. The stuff that doesn't seal a leak just circulates through the system, it's only on exposure to air that the reaction seems to happen. If you want to remove it, just flush the cooling system - although if you do flush/change the coolant without sealant the leak will come back as the 'solidifed' sealant will slowly erode over time. I stick to the more expensive brands that use suspended small aluminium/copper particles which seem to work far more reliably. Again, it should only be considered a temporary fix but can last a fairly long time. I've seen one, at least temporary, good improvement from an application of head gasket sealant. Definitely brought the car into a drivable state, prevented overheating and stopped coolant pooling in the cylinder(s) when the engine sat switched off. Again, it's just a bandaid but waaaaaaay cheaper than the alternatives.

[@SchrodingersBox]

Yes Carnivore is correct. It is totally different than say, a radiator seal. This block sealant is not goopy at all- quite the opposite in fact It only changes in presence of the extreme temperatures in a combustion chamber. In fact I would argue leaving it in actually helps to secure the leak better if it starts to fail.

[@JohnDoesGarage]

I'm of the same school of thought as you when it comes to products that claim to fix blown head gaskets. Obviously from your experiment it did make a significant difference, but I have my reservations as to how long it would last. I'm guessing since the compromise appeared to be a small passage between the combustion chamber and the water jacket is why that product worked as well as it did. The compromise is probably a crack as opposed to a portion of the gasket being blown completely out in which case you would have seen evidence of that in all of your tests and I doubt the product would have made any difference. Personally, I'd tell the owners to fence the Jeep as is with no guarantee. I have no idea how long it would run like it is, but odds are it will not be a permanent repair lasting the remaining life of the vehicle and when it fails the next time, it would be of a more catastrophic nature risking them being left stranded in an inconvenient place. Err on the side of caution is my mantra. These three videos were fantastic. Thank you for taking the time to make them.

[@SchrodingersBox]

Agreed 100%. We are totally aligned. Even if it works, it’s still not fixed.

[@Agent-nw3it]

I am surprised that the first shop didn't try to sell this fix. I guess it really must be working :) But realistically, if a metal head gasket fails after x-thousand miles, this product surely at some point will too.

[@SchrodingersBox]

Good point!!

[@fredflintstone4715]

A couple of years and 15K miles ago, I had a blown head gasket (according to the blue liquid chemical test). I used the Barrs 'bandaid in a bottle' fix similar to the Blue Devil, and haven 't had any problems since. Haven't done any compression test though. And since it's a manual, it hasn't seen but MAYBE once anything over 3K rpm. Don't know if that would make any difference...

[@scottwoodbury5777]

Great video, Thank You for the excellent content. The real snake oil test will be a quick drive up and over one of the mountain passes to the west of you!! Maybe around town within easy reach of a tow truck -yes, but the longevity of such a "repair" is always in question. I just wouldn't trust it.

[@SchrodingersBox]

Hahahaha yeah there is no way I would risk that lol but it would be the ultimate test.

[@jum5238]

@@SchrodingersBox And invite a friend to follow in a tow truck.

[@DependableAutoTruck]

one thing i have found it really good at is stopping up the heater core. i have one customer who said he sealed head gasket for about a year

[@SchrodingersBox]

Amazing, Howard. If this lasts even a few days I will be amazed.

[@DependableAutoTruck]

@@SchrodingersBox it is used a lot in the south and they give a money back warr if it doesn't work. I personally will NOT use any of the stop leaks not even the ones for radiators

[@thecolliman7674]

Awesome video Matt big 😊 from across the pond

[@SchrodingersBox]

Thank you!! Many viewers from there and they are always the best!

[@vieczurable]

In first test there is a small but noticeable narrow gap (I know we are looking for difference in height) from a bottom of the wavelet. Interestingly, it seems to correlate with one of cylinders during a test. Out of curiosity, because nobody ever address that phenomenon I wonder where this gap width difference originates from and if it is indeed related to the faulty cylinder? My first shot would be for a gasket allowing to pass exhausts to next cylinder in which any of valves is open.. So loss of pressure results in wavelet's gap thickness difference.

[@billylamar5218]

Best part of the whole video was the knee slapping bit when watching Kilmer blow cigarette smoke as a smoke machine I’m guessing 😂 I died.

[@SchrodingersBox]

Hahahaha glad you appreciated that!!!! I still can’t believe that guy is even a thing.

[@mikemurphy7519]

Can you do a burn test on the coolant after adding the bluedevil to see if you can see a difference in the reaction so that we can have a test to see if someone put this chemical in the cooling system?

[@SchrodingersBox]

Good question!! When car comes back I will take a sample of the coolant and see if we can do something to identify it! Some products recommend replacing coolant after it "works" so there is always that variable to consider.

[@jum5238]

Question (since I was honestly fighting sleep - late hour, but I didn't want to forget to watch this again). No scope, vacuum gauge, you see the needle move. Was the decision path just to claim there's a compression failure and notify the person, or was there a fast way to continue and isolate the cylinder without having to check each cylinder respectively. I know you had a misfire code to go from, but if not... was there a way? (I like the scope/transducer trick, but.. $$$$$$??? No, can't afford that).

[@salvadorgutierrezr5914]

Amazing thanks for teaching Mat 🙏 God bless you

[@SchrodingersBox]

You are welcome my friend!!

[@user-pl7cg2yc4o]

Have you ever looked at the top of the piston to see if it looks like someone steam cleaned it?

[@Netherlands031]

24:45 that's one noisy signal, have your turned on oversampling when recording it? Or you can just enable the low pass filter in Channel Options

[@thecardoc100]

I had to speed through the video's so I might have missed some details. If there is one thing that is missing in the trade it is giving credit to the people who figure these tricks out and then share them. Adam Robertson one of the CTI instructors is the person who came up with a number of the ideas that were shared here, including using the blood pressure cuff, which does work BTW. One of the worst things about the sealants isn't questioned about whether they work or not because there is room for them to do so as you have seen. The problem is they can also restrict coolant flow in places where coolant flow is needed or make detecting a failure or it's location undetectable for some random period of time. I have seen a cylinder head sent out to a machine shop for testing that passed and was put back into service that caused a repeat failure and the shop had to eat the second repair including the cost of the replacement cylinder head. We will leave heater core (and other) failures cause by sealants for another time. MLS (multi-layer Steel) gaskets used in today's engines allow for different rates of expansion between the cylinder heads and the block. Anyone that has replaced head gaskets through the years often appreciates one notable difference with them and older designs is that we encounter a lot less debris bonded to the cylinder head and block gasket surfaces with these gaskets making the cleanup work be a lot easier before reassembly. However, the RA of a prepared gasket surface is much lower with MLS gaskets and improper surface prep can result in short gasket life. This is important when considering how the sealants work, between expansion/contraction cycles and the abrasive nature of the sealant compound we could end up with a surface finish that will be prone to repeat failures and there is nothing at a shop level that we can do about it besides replace components. I would advise repeat the radiator testing with a Delta Pressure Sensor as compared to an Absolute Pressure Sensor. Credit Brandon Steckler for that insight. I'm sure this was eye-opening for a lot of the viewers, for us finding internal engine problems that were undetectable with basic compression testing is just par for the course. Today we have engines where the manufacturer does not publish compression specifications. Since variable valve timing could come into play during cranking you cannot really be sure what the compression should be beyond consistent across the engine. Just wait until you see an engine with a "variable compression ratio" on top of variable valve timing.

[@ivanhoe6366]

Quality content right here. Thank-you.

[@robmut1357]

Excellent video!! All the way around. Excellent. 👍👍(two thumbs up) 😁

[@SchrodingersBox]

Thanks as always Rob!!!

[@topgun52]

Hey Matt, great video I appreciate the time in making it. Would you ask Vicky where she picked up that Borescope? Thanks

[@SchrodingersBox]

Thank you! She got it here: www.amazon.com/dsfen-Borescope-Multifunctional-Endoscope-Industrial/dp/B0BLVTP7CV/ref=mp_s_a_1_3?crid=29MEDMFBRIAU4&keywords=borescope+finder&qid=1684913735&sprefix=borescope+finder%2Caps%2C113&sr=8-3

[@topgun52]

@@SchrodingersBox Thanks! Can't wait to see the fellow-up video to see how the "Blue Devil" treatment holds up.

[@nukesploder]

Hi Matt, great video btw! I'm glad of this series and its great to see you being so enthusiastic about car repair! You've really done some great stuff and im glad to have supported*** you on quantum mechanix. I have a separate question from the material above so feel free to ignore if it doesn't strike your fancy (lol) I'm wondering if you'd be able to sometime do a video on some of the cheaper tools that have come out that might be more necessary now than before when it comes to auto diagnostic. I'm referring to: buying a scan tool, buying an oscilloscope, AMP clamp and the like. Do you think that there could be some good entry level tools to buy? Thanks so much! And great video BTW

[@SchrodingersBox]

Thanks for your support!! I actually have a lot of that on my pay channel including "scan tool overview" where I compare several scnatools and how to purchase one, I also have a garage tour with all of my tools shown, and I also have a complete overview of the Vantage Pro. But at the same time I have lots of stuff since then. How about I do another garage tour and we cover some of my budget tools?

[@nukesploder]

@@SchrodingersBox i think that'd be awesome! I'd love to see that. Thanks for your response!

[@mark303murphy]

I tried blue devil in a very similar head gasket leak situation, similar results with the 99% improvement. 3-4 days later it was overheating as bad if not worst than it been when I first looked at it. Complete waste of money and time.

[@SchrodingersBox]

Yep that what I expect we will see on this car as well. I don’t even expect it to last a week.

[@javiTests]

Another test you can do after a week with that "fix" (my gut tells me it's not going to last for long, let's say more than 10k miles to be scientific 😅) is the one to detect CO2 in the coolant. I guess it's not going to pass since the coolant creeps up when you put pressure in the cylinder, meaning there is some contact between gases and coolant, but who knows... I think that was done in another channel on a porsche 911 with a bad head gasket and it passed, but I don't trust that guy to tell the truth 😂. In any case, to be fair, he said that if it worked, it was going to be a temporary fix at best. By the way, these videos are more interesting than any TV show and at the end you learn something! One of my favourites on your channel.

[@calholli]

hahahah.. So conclusion, when your ingress leak is small enough that it doesn't show up in your relative compression test, there is a good chance that it can possibly be fixed with the aftermarket stop leak routine. Very cool. But I would bet, if it's bad enough to show up on your relative compression test, then the leak is far too large for the stop leak stuff to work. Very interesting results. I'll be interested to see how it does after a decent highway trip..... Which that does actually make sense when you think about it: If you're not losing compression, that means it's not blowing pressure back into the coolant- which would blow away the stop leak stuff; so the "pressure" is only coming from the coolant side trying to push into cylinder, which is what holds the stop leak product in place. I'm not exactly sure how that happens, but it is measurable. The relative compression test tells the story IMO; it says "this leak is possibly fixable", when it doesn't show any compression loss. Seems like a very rare and specific situation, and it's pretty cool that you managed to capture the whole story as it unfolded. lol..

[@labradormcgraw]

I guess you could have repeated the sizzle test after the Blue Devil treatment - just as a complete before-and-after example - but it certainly appears that this remedy has worked. And LMAO at a certain KZbinr's cameo in the video. "Start your engines!" 🤣

[@SchrodingersBox]

Well Andy the thing is the sizzle test will be positive on this car even if it is fixed until several oil changes because of all the contaminated oil.

[@labradormcgraw]

@@SchrodingersBox Oh, yes - of course. I was thinking the oil had been changed, but that was the coolant. You’ll have to forgive me; I turned 50 last month, and I think I’m already losing a step. 😟

[@SchrodingersBox]

I am 53 so believe me I am right there with you hahaha.

[@InsideOfMyOwnMind]

This was QM++ stuff here. I would challenge the likes of Scanner Danner to get this real in a diag. Super super impressed. So unbelievably cool to see that stairstep and when you correlated it to cyl 7 it was like having ("caustic" term deleted here.🤣) Now what you need is a bore scope with a mig tip on it so you can go in and just weld the leak shut......right???🤣 OK that was a joke....I think. Stellar video.

[@SchrodingersBox]

thanks man!! yeah pretty satisfied with this one. love the mig-scope idea hahaha

[@jum5238]

@@SchrodingersBox Until you touched the tip and it got stuck in the cylinder. Then it's like having a certain part of your body stuck in a zipper and being too painful to move it to free yourself, because then you're doing a head job around a stuck welding setup. Similarly embarrassing as well.

[@calholli]

IMO, you should ALWAYS use an attenuator when probing coils-- simply because of the off chance that your coil could be bad or have a hole and spike through the rubber boot and hit your scope. Any time you're near the coils, you should be using a 20x attenuator. You're just rolling the dice, hoping that you'll never cross a faulty boot (as unlikely as it may be); it only takes one. lol. You can order cheap probes for less than $20 that have the little switch on it, with a built in attenuator right on the probe.

[@InsideOfMyOwnMind]

And that little transistor at the front end of your scope's input channel will cost you more than the price of the scope if you bork it with a rogue EMP.

[@DIABLO_4_Tester_Sacramento]

how to determine, do I have pushrod tick, rocker arm or valve lifter ticking ?

[@SchrodingersBox]

you have to determine that visually. once you determine you have a top end noise as opposed to bottom end noise you have to then examine it.

[@sheerwillsurvival2064]

Can’t wait for next video

[@SchrodingersBox]

Yes we will just do a follow up on this vehicle in a couple weeks.

[@sheerwillsurvival2064]

@@SchrodingersBox 👊🏻

[@kerryb2689]

I'm about a month late, but could you use the video to record the ignition sync And the vacuum gauge simultaneously (or a water manometer =clear plastic tube filled with water) to determine which cylinder? You would have to count video frames between ignition signal and know how many frames per second.

[@SchrodingersBox]

Really good idea- yes you could do that!!!

[@amt1298]

I hope you use K-Seal because out of all of them, it would be the only one I would try.

[@SchrodingersBox]

why is that?

[@amt1298]

@Schrodingers Box The guys on the Under the Hood Show never use snake oil but a customer was in a pinch and so they gave it a try. They couldn't believe it worked either. They never recommended anything unless they use it, see that it works and works well.

[@SchrodingersBox]

Similar to this situation, it sounds like it was more the conditions than the product itself. In other words it could be that any product would have worked in this exact situation with a leak so minor there was no compression loss

[@zachshomerepair]

Now I gotta try this on my vehicle with a vacuum gauge…a little nervous about the results

[@danieljurgill1681]

So how does the ECM determine a misfire ? Is the computer measuring a spark event high voltage across the gap, or does it somehow unknown to me measure a actual combustion event ? So if we had good spark and adequate compression , it must have been the ingress of coolant from the intake stroke vacuum, perhaps negative 7 psi , and the pressure in the cooling system, which adds from zero to 15psi cap rating as the engine heats up, and added together cause a 7 to as much as 22 psi differential force from the coolant side of the gasket thru into the cylinder side. There is a cylinder standard compression gauge drop of something, but it is so small , perhaps only 1 psi, which would not be detectable with any standard gauge. If you push on your car with a hammer in your palm , you could move the car, but if you use the hammer to hit the bumper the car will not move.

[@SchrodingersBox]

It known in a P030x code by sensing slightly slower crankshaft speed after that cylinder fires. Also it can tell if an ignition coil itself failed to fire which would indicate a coil circuit specifically.

[@sylvainblanchet3390]

Awsome i was waiting for this video .

[@SchrodingersBox]

Hahaha me too. It wont disappoint. Will answer everything and then some.

[@brianelliott6148]

Hey at 23 mins and a half you were counting the cylinders I noticed there were spikes on all but the 7th cylinder is that correct bc they looked a little different I believe it's the spike?

[@SchrodingersBox]

The ignition spikes are only on number 1. All else is just background noise from the coils.

[@bleebleblahble8833]

The vacuum gauge is probably easily adaptable to the caps from a coolant system pressure test kit

[@bleebleblahble8833]

In fact a radiator pressure tester alone might work. If pressure builds without pumping.

[@SchrodingersBox]

YES!! You can totally do that. Its just that radiator pumps usually have very poor low pressure resolution on the dial. It will be really hard to see those "steps" without something much more sensitive.

[@jum5238]

@@SchrodingersBox Maybe it's being too cheap on my part, but I've never had good luck with the autozone pressure tester kits they loan out, as (I'm guessing) it's well used and can't form a good seal. Or, the adapter fitting I need doesn't exist in the kit or is missing. My luck/little black rain cloud)

[@nickayivor8432]

Enjoy your weekend with all your family around you ,Schrodingers box Outstanding tutorial, thank you very much 👍 ❤ it SHARP Schrodingers box From Nick Ayivor from London England UK 🇬🇧 ⏰️ 21:56pm

[@SchrodingersBox]

We are enjoying to the Memorial Day weekend here in the states!

[@settjessettje9323]

Are you familiar with labyrinth seals? It is possible you have a similar phenomenon In that head gasket leak 😊

[@SchrodingersBox]

Never heard of that!

[@lesliebarnett-tx3jf]

Great video

[@chunjee]

I called the local junk-dealers and they all use K&W FiberLock Block Repair these days Glad the Jeep had some improvement

[@justinsmith623]

And if you never want to miss another one of my new car repair videos, don’t forget to ring that bell! LMAO 🤣

[@MrCook-kl2qe]

Vice Grip Garage used K-Seal on one of his revivals and worked.

[@SchrodingersBox]

Did he show before and after compression test results?

[@MrCook-kl2qe]

@@SchrodingersBox No. He was doing a revival and was traveling.

[@SchrodingersBox]

Then he technically didn’t show that it worked I have yet to see any other videos that scientifically test such products.

[@davejones3170]

Why do you hold the crank on bottom dead center? Won't the air pressure hold the piston down"

[@SchrodingersBox]

because at true bottom dead center the intake valve is still open so I would lose the pressure.

[@mikemurphy7519]

Well then, to be more specific, don't call it BDC, call it near BDC

[@SchrodingersBox]

I never called it BDC in the video if you noticed- I said I am holding it at bottom of the compression stroke. That would never be at BDC, right?

[@derekspaar782]

Do you ever Watch Pine Hollow Auto Diagnosis on KZbin he is really good and he sell Pressure transducers and I thought the engine had some Moisture in the engine oil from atmospheric air getting hot from Combustion events love your videos

[@SchrodingersBox]

I haven’t watched him in years- I only watch scannerdanner really. I have been told about the transducers.

[@derekspaar782]

Sannner danner is good south main auto is really good Eric o. Is funny and he is really good

[@ytwatcher8288]

Given that the design of the gasket is intended to seal under pressure, perhaps you have here the mechanical equivalent of an electrical diode...

[@mrautoguy8419]

Great video! I have a question. You say you are a Scientist. What kind of Scientist work you do? If you dont mind me asking. I been curious about that for years lol.

[@SchrodingersBox]

I am a molecular biologist. specialize in genetics, dna and rna, proteins, viruses and anything that modifies any of the above.

[@mrautoguy8419]

@@SchrodingersBox That is pretty cool!

[@boduke2299]

What is the make and model of that bore scope where could I get one thanks.

[@SchrodingersBox]

Its called Finder Borescope from Amazon

[@boduke2299]

@@SchrodingersBox thanks I appreciate it.

[@zanzeroth]

Any stop leak is just a bandaid. It gives you the chance to save up for that expensive repair.

[@SchrodingersBox]

Yes I strongly suspect this will not last long. I am just impressed it even made a difference at all.

[@JimFinlayson]

Your videos are great. Probably beyond my skill but you greatly improve my knowledge. You obviously have more followers than some full timers, but your altruism is apparent and youtube $$ allow you to reinvest in better and better diagnostic tools.

[@SchrodingersBox]

Thank you very much and yes, you outlined my strategy quite well.

[@tracycolorado]

Atta boy 🎉

[@denrayr]

I wonder if securing a nitrile glove to the top of the radiator would be sensitive enough to see the pressure buildup for a poor man's test. If anyone reading this is confused with the cylinder math, there's 720 degrees of engine rotation between each firing event for a single cylinder. With 8 cylinders, 720/8 means there's 90 degrees between each cylinder firing event. If this was a 6 cylinder engine there would be 720/6 = 120 degrees between each cylinder firing event.

[@reneneron2971]

Yes, it would. So would a balloon. Or a plastic newspaper bag. Or a condom. But the glove would work. I suspect the pressure would continue to build until released by the radiator cap.

[@SchrodingersBox]

Yes the pressure would increase enough for sure but I imagine it might take several minutes of cranking before you see it.

[@jum5238]

@@reneneron2971 I'm sorry... (busting a gut here, and I'm punchy/tired/exhaused) I'm just imagining a condom unfurling and the customer (or wife) walks in and wants to know what's going on. (see my other comment about the ghetto PVC and spray paint)

[@reneneron2971]

@@jum5238 just tell them the engine is f#&@(‘. due to a blown head gasket.